Dynamic receive aperture transducer for 1.5D imaging

Abstract

An ultrasound imaging system enables 1.5D image information to be generated from a single firing of a linear transducer array by permitting dynamic control over the receive aperture. The imaging system comprises a transducer having a linear array of piezoelectric elements arranged in a plurality of distinct rows of the elements. The transducer is operable to provide acoustic pulses from elements of a first one of the rows in response to respective driving signals and to provide corresponding return signals in response thereto at elements of additional ones of the plurality of the rows and at the first one of the rows. A receiver is coupled to the transducer to receive a summed signal corresponding to the return signals from the elements. The receiver comprises a plurality of low voltage switches that couple to respective ones of the additional ones of the plurality of the rows, and a high voltage switch disposed in series with the low voltage switches. The timing of the high and low voltage switches is controlled to vary the focusing characteristics of the imaging system. A processor coupled to the receiver and the transducer generates a 1.5D image using the summed signal.

What is claimed is: 
     
       1. An imaging system, comprising: a transducer having a linear array of piezoelectric elements arranged in a plurality of distinct rows of said elements, said transducer being operable to provide acoustic pulses from elements of a first one of said rows in response to respective driving signals and to provide corresponding return signals in response thereto at elements of additional ones of said plurality of said rows and at said first one of said rows;   a receiver adapted to receive a summed signal from said corresponding return signals of said elements;   a processor coupled to said receiver and said transducer to provide a 1.5D image from a plurality of said summed signals; and   switch means for coupling said transducer to said receiver, said switch means comprising a first switch element coupled to respective ones of said additional ones of said plurality of said rows, and a second switch element coupled between said first switch element and said receiver.   
     
     
       2. The imaging system of claim 1, further comprising means for controlling timing of said switching means. 
     
     
       3. The imaging system of claim 2, wherein said controlling means further comprises an active network. 
     
     
       4. The imaging system of claim 1, wherein said first switch element further comprises a plurality of parallel-coupled field effect transistors. 
     
     
       5. The imaging system of claim 1, wherein said first switch element further comprises a signal pass element and a complimentary charge injection element coupled in series. 
     
     
       6. The imaging system of claim 5, wherein said signal pass element further comprises a plurality of parallel-coupled field effect transistors driven by an elevation signal. 
     
     
       7. The imaging system of claim 6, wherein said complimentary charge injection element further comprises a plurality of parallel-coupled field effect transistors driven by a complement of said elevation signal. 
     
     
       8. The imaging system of claim 1, further comprising a transmitter coupled to said transducer to provide said respective driving signals. 
     
     
       9. The imaging system of claim 1, wherein said first switch element further comprises a low voltage analog switch associated with each one of said additional ones of said plurality of said rows. 
     
     
       10. The imaging system of claim 1, wherein said second switch element further comprises a high voltage analog switch. 
     
     
       11. In an imaging system comprising a transducer having a linear array of piezoelectric elements arranged in a plurality of distinct rows of said elements, a method for providing a 1.5D image comprises the steps of: emitting a set of acoustic pulses from respective elements of a first one of said rows in response to respective driving signals;   receiving corresponding return signals in response to said set of acoustic pulses at elements of additional ones of said plurality of said rows and at said first one of said rows;   coupling said return signals from said additional ones of said plurality of said rows and said first one of said rows into a receive path of said imaging system by controlling a plurality of first switches and a second switch disposed in series with said plurality of first switches; and   forming a 1.5D image from a beamformed sum of said return signals.   
     
     
       12. The method of claim 11, wherein said coupling step further comprises the step of closing said second switch after completion of said emitting step. 
     
     
       13. The method of claim 12, wherein said coupling step further comprises the step of closing respective ones of said first switches in a sequential manner during said receiving step and subsequent to closing of said second switch. 
     
     
       14. The method of claim 12, further comprising the step of controlling timing of closing of said first switches.